不同生境下氮沉降对土壤N_(2)O通量影响的整合分析

Meta-analysis on the effects of nitrogen deposition on soil N_(2)O flux in different habitats

基于在我国开展的66个野外氮沉降模拟试验的290组数据,采用整合分析方法,探究实验样地特征(气候因子、土壤性质)和施氮因素对施氮后土壤N_(2)O通量变化的影响。结果表明:样地的年均降水量、年均温、自然氮沉降量和土壤C/N与施氮后N_(2)O通量增幅呈显著正相关,土壤pH与施氮后N_(2)O通量增幅呈显著负相关。湿地生态系统土壤对施氮最敏感,森林生态系统次之,草原生态系统最小。所有的样地因子中,土壤pH和C/N对施氮后N_(2)O通量变化幅度的影响最大。施加硝态氮后土壤N_(2)O通量增幅最大,施加尿素与铵态氮后N_(2)O通量增幅相当,而施加硝酸铵后N_(2)O通量增幅最小。综上,在准确评估和预测土壤N_(2)O通量对氮沉降的响应时,应综合考虑样地特征及氮源种类的影响。

We carried out a meta-analysis to explore the effects of site characteristics(climatic factors and soil properties)and nitrogen(N)factors on soil nitrous oxide(N_(2)O)flux after N addition based on 290 data from 66 field N addition experiments in China.The results showed that mean annual precipitation,mean annual temperature,ambient N deposition rate,and soil C/N of sites were positively correlated with the increases of N_(2)O flux after N addition.Soil pH was negatively correlated with the increases of N_(2)O flux after N addition.Furthermore,soils in wetland ecosystem were most sensitive to N addition,followed by forest ecosystem,and grassland showed the lowest sensitivity.Among all the site characteristics,soil pH and C/N were the most important factors driving the responses of N_(2)O flux to N addition.Soil N_(2)O flux increased the greatest after nitrate addition.The increase of N_(2)O flux was similar after the addition of urea and ammonium,while N_(2)O flux increased the least when ammonium nitrate was added.In summary,to accurately assess and predict the response of soil N_(2)O flux to N deposition,the effects of site characteristics and N fertilizer types should be comprehensively considered.